BANNED

When I was in high school, my parents took me on vacations in the southern U.S. I remember well being in some North Carolina motel when the DDT foggers came through in the evening. I walked around in the mist as I unpacked the car. Little did I know then, in my early teens, that it was other than an unalloyed boon. (To be clear, I suffered no ill effects myself. But of course I had only a single brief exposure.)

There has been much dispute over the worth of pesticides, primarily over DDT because of its unique history. Developed at Germany's I. G. Farben in 1937, it quickly became popular and — ironically for the Third Reich — proved a great boon to the Allied Powers in World War II, especially in the Italian campaign where it protected the troops from typhus.

After the War, DDT was produced in massive amounts by U.S. manufacturers. The manufacturers found ready markets in the agriculture industry, where DDT swiftly controlled all manner of crop pests with little apparent harm to humans or wildlife. But within a few years it became clear that DDT was having major impacts on wildlife populations where it was used. These impacts have been extensively documented. In the same period, medical doctors began to notice harm to humans. Damage to kidneys, liver, and the nervous system were discovered. Such damage required long-term exposure. But that is why DDT and the other insecticides in its class, the chlorinated hydrocarbons, are so insidious: they persist in the environment and collect in fatty tissues. Thus, those who eat fruit with DDT residue over a long period can suffer various kinds of chronic illness. However, getting a DDT preparation on your skin while applying it will do no harm as long as you wash it off promptly.

DDT's other problem is that many pests, including houseflies and mosquitoes, can rapidly become immune to its effects. So can the malaria parasite. Use of DDT was banned in the U.S. in 1972, after contentious congressional hearings where testimony revealed the newly discovered problems. It is still made here, and used in many places overseas. It is a genuine boon if applied properly. Unfortunately, many factors combine to impede proper use.

This ban is doubly unfortunate because it has led to substitution of other, more dangerous pesticides for DDT. Chief among them are the organophosphates1 including parathion and monocrotophos.2 In the long battle with crop pests and vector-borne diseases like malaria, we have often wielded chemical weapons we did not really understand. Tragedies have resulted. But we do learn, in time. The author shows us the work of the toxicologists who gave us that understanding — a knowledge still incomplete, but improving. The declining uses of pesticides, as shown in the tables I provide below, are indications that we are growing wiser about pesticides.

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This page was last modified on 12 September 2024.